[Bug]: Skill import size limit blocks imports and manually added .Agents/skills are not auto-loaded

Deployment type

Official App

What happened?

github import: skills/dashiai-ppt/assets/skill/theme-style-grid.png: import cap exceeded: file exceeds 1048576 byte limit

Steps to reproduce

1.skills 2.从URL导入 3.https://github.com/chuspeeism/dashiAI-ppt-skill，导入

Screenshots (optional)

Additional context (optional)

建议：
方案一：调整大小限制，支持自定义配置
方案二：支持从本地skills仓库导入或者自动加载，比如支持从现在默认的公共的.Agents/skills目录读取加载